1. Field of the Invention
The present disclosure relates to an insulation detection circuit and method thereof; in particular, to an insulation detection circuit and method thereof which are applied between a high voltage power and a low voltage power of a vehicle.
2. Description of Related Art
According to the progress of the technology, the transportation vehicle is provided with versatile electric instruments such as the illumination lights, the electromotive windows, the digital video/audios, the navigation systems, or the isothermal air conditioners, etc. Those electric instruments are operated by using the power supplied from the battery, the electricity generator, or the high voltage to low voltage converter. Of course, there needs a good insulation between the high voltage power and the low voltage power of the vehicle, for making people use versatile electric instruments safely.
However, the progression of the vehicle goes toward the hybrid vehicles or electric vehicles of green energy industry, and the electric vehicle may output a high voltage of about 60 to 600 volts by means of, for example, a driving chain including the high voltage battery and the high voltage to low voltage converter. However, the high voltage exceeding 60 volts is considered to be harmful to people.
When the insulation between the high voltage power and the low voltage power of the vehicle is damaged, the current may leak to the chassis or the shell of the vehicle, thus the chassis or the shell of the vehicle may contain the charges which are harmful to human body. If the user touches any part of the chassis or shell of the vehicle, the user may be hurted by electric shocks.
For example, when the vehicle is subject to strong vibrations, thus the insulation body is abraded or cracked mechanically, such as the insulation body damage of the high voltage cable of the vehicle. Thus, the current of the high voltage power may leak to the shell of the vehicle. For warning the user, driver, and passenger of the vehicle about the leakage current caused by the damaged insulation body, the vehicle needs to be installed with the insulation detection circuits for detecting the condition of damaged insulation which may happen.
Therefore, the abnormal insulation status between the high voltage power and the low voltage power of the vehicle is a serious problem which needs to be detected, for ensuring the safety of the people who may touch the vehicle. Thus, how to improve the accuracy of the insulation detection circuits during operation is an important topic.